I don't fit your criteria but I am commenting anyway. I am in my seventh year of what started as pmr and gotten sidetracked with other seemingly inflammatory conditions. I am stuck at 3 mg prednisone for the time heing.
I will not get another covid booster. The last one had me feeling bad enough that I feel getting another one would be tempting fate to set off a very bad reaction.
It seems from some of the articles I have read that the flu shots are not always effective against the predicted viral strains. I did not get the flu vaccine last year. As of now, I do not plan on getting another one.
From my experience with all of this, I would suggest you maintain a healthy anti-inflammatory diet as much as possible and be especially mindful if flu or covid is spiking and you have opted not to get vaccinated.
Having tried to taper below 3 mg twice already, I have definitely felt fatigued. I guess I'm blaming low cortisol?.
Maybe your adrenals are still trying to recover completely.